*Touches wood*
I haven't done it... yet.
As an apprentice I did once pour screen wash down the oil filler tube on a SedAk wagon, in my defence the oil filler was where the screen wash filler would be on a Foden (which I was used to working on).
I had sloshed 3 gallons in, thinking "wow the screenwash bottle is massive on these Atkis, that'll do."
Luckily it had had an oil change, and the fitter who did it dipped the oil before the owner turned up, realised what had happened and we changed the oil quick time, just putting the filler cap on as the owner/driver strolled into the garage to collect it.
I still shudder to think what would have happened if he started it.
I learned my lesson.
A friend of mine once took his Seddon Atkinson lorry in for a service. He told me after that for some reason it kept blowing out bubbles from the stack behind the cab . . .
Only kidding😂